Locking device for folding cranks



(No Model.)

D. F. LATIN. LOOKING DEVICE FOR FOL-DING GRANKS.

No. 503,747. Patented Aug. 22, 1893.

UNITED STATES PATENT OFFICE.

DAVID F. LATIN, OF CLINTON, MASSACHUSETTS.

LOCKING DEVICE FOR FOLDING CRANKS.

SPECIFICATION forming part of Letters Patent No. 503,747, dated August 22, 1893.

Application filed November 25, 1892. Serial No. 453,029- (No model.)

To all whom it may concern.-

Be it known that I, DAVID F. LATIN, of Clinton, county of Worcester, State of Massach usetts, have invented an Improvement in Folding Cranks, of which the following description, in connection with the accompanying drawings, is a specification, like letters and figures on the drawings representing like parts.

In the construction of folding cranks where the handle is pivoted to the crank arm and is adapted to be moved outwardly therefrom to a position at right-angles thereto, it is desirable in some instances to have the handle automatically locked in its extended position so that a quick pull will throw the same into place, and it is also desirable,if alock is used to prevent rotation of the crank when not in use, to provide means for releasing said lock when the handle is extended and the crank is thereby made operative.

This invention has for its object the production of a folding crank the handle of which is pivoted to a crank arm so as to be turned in upon or adjacent to the same when not in use, the folding of the handle removing the the same out of the way, the crank having devices for automatically locking the handle in extended position and devices for holding the crank arm in fixed position when not in use, the latter devices being actuated by or through the pivoted handle.

In accordance therewith, myinvention consists in the combination in a folding crank, having a crank arm and means to lock the same from rotation in either direction, of a handle pivoted to said arm and controlling by its pivotal movement said locking means, substantially as will be described' Also in a folding crank, a crank arm having a longitudinally movable locking pin, combined with a crank handle pivoted to said arm, a spring controlled bolt to automatically engage and hold the handle extended, said handle being adapted when closed to co-operate with and force the locking pin into engagement with a suitable catch, and means to withdraw the bolt from the handle, substantially as will be described.

Other features of my invention will be hereinafter described and particularly pointed out in the claims.

Figure 1 represents a side elevation of my improved crank, partially broken out, the handle being shown as extended. Fig. 2 in side elevation shows a portion of an extensible ladder with my invention applied thereto. Fig. 3, on an enlarged scale is a section taken on the line 00, 00, Fig. 1. Fig.4 is a detail showing the handle closed and the crank arm locked from rotation.

I have herein shown the crank arm a as secured to the squared or polygonal end of the winding shaft A of any hoisting device, the same being supported in hearings or standards B, only one of which is shown in Fig. 1, the outer end of the crank arm being provided with projections or ears a, between which is pivoted at e the reduced portion h of a suitable handle h. A headed bolt ehaving a rounded inner end 9, see Fig. 3, is held in a recess in one of said ears 0. by a preferably threaded bushingf, and a suitable spring g, held as shown in Fig. 3 between the outer end of the bushing and a pin or projection g on the bolt, tends to force the rounded end of the bolt inward. The reduced portion 77/ of the handle is provided with a transverse recess 9 see Fig. 3, which is adapted to be entered by the said bolt when the recess is brought in line therewith as the handle his rotated upon its pivot e into the position shown. in Fig. 1, so that the handle is automatically locked in said extended position by the engagement of the bolt with the recess.

When it is desired to fold the crank the head of the bolt 6 is grasped and the bolt drawn outwardly against the action of the spring, removing it from the recess 9 whereupon the handle h is free to be moved upon its pivot and brought into the position shown in Fig. 4. So long as the crank is folded the bolt 6 rests upon the side of the portion h", but the instant the handle is turned in to the position at right angles to the crank the bolt slips into place in the recess and automatically locks the handle. Tension of the spring may be regulated by rotation of the bushing f.

When thecrank is folded it is desirable to provide a locking device forthe same, which will prevent rotation of the crank arm, and I have herein shown one convenient form of 5 locking device, the same consisting of a pin" 19 extended through the crank arm, the latter being hollowed out at. c:t receive a spring b'j resting against a suitable enlargement on the pin, the pin being retained inplace by. suit-.

1c able bushing b herein shown as threaded.

The ends of the pin b project beyond the arm a, the outerend being adapted to enter a recess" d, see dotted lines Fig. 1,'in a plated r 5 screws 2. The opposite end of said pin pro-- -jects into the path of movement of and is engagedby a part of the handlewhen: the.1 at-,

ter is folded, see Fig. 4, forcing thepi-n-b out,

wardly against thepressure ofv spring 1) and; 2 o:i-nto engagem-ent with the recess (1' of the.

[catcher plated. When the handle is un-,..

foldedv or drawn out, thepin b ;is "withdraw ng from engagement with the cat-chthroughthe action of the spring bandthe crank is free" .to be rotated.

In Fig. 2 I have shownmy inventionas applied to an extensible laddenthe shaftAbe-g =ing-rigidlyattached to the winding drum, and.

I "have, secured to the ladder side L two catches;

3.0 d,.one.above and onebelow the-shaft,;:s0that ,the crankmaybe held in its lower or upper position, as desired: and most convenient.

From the-foregoing it will be seenthat'the folded crank, herein described, is of such}:

5 construction that whennot in use it maybe locked-from rotation, the locking device be .ing operated by the act of closing. or folding "the handle it and released by theunfolding; of said handle, the latter being providedw-it hg. 0a device for. automatically locking itin posi 'tion when fully extended.

I do not wish'to restrict myself to the pro- .cise construction or arrangementof parts as herein shown, as the same may be-somewhat, varied and their relatlve arrangeme-ntaltered same-rm .and controlling by itspivotal movement said locking means, substantially as described.

'2. In a foldingcrank, a crank arm having a longitudinally movable locking pin, combined with a crank handle pivoted to said arm, a spring controlled bolt to automatically secured to the shaft support B by suitable ii engageandhold-the handle extended, said handle being adapted when closed to co-operate with and force the 10c-kingpin=into en"- gagem-ent with a-suitable catch, and means to withdra'wthe boltfromtthe handle, substantially. asdescribed. V

' 3. In hoisting mechanism for extensible ladders, the combination-with a crank arm, a normally retracted locking pin carried thereby,.and a fixed catch ofa pivoted handle adapted to force said pin into engagement with the catch toprevent rotation of -the arm,

substantially. asdescribed.

.4. In hoisting mechanism fonextensible ladders, gthe combinationwith a crankarm, a spring-controlled .bolt .carried thereby and having its inner end normally imposition to enter arecess in a handle, and; a locking pin forand-carried by the crank arm,of a handle pivotedato .thecrankwarm-and .pr0vid.ed with a -transverse.bolt receiving recess, folding, of

.; the handlenpon thearm operatingsaid locking pin to prevent rotation fsaid arm in either direction, substantiall y as described.

Intestimony whereof Ihave signed my name to this specification in thepresence of two subscribing witnesses.

DAVID F. LATIN.

- Witnesses:

.ISAAC J. FLAGG, JOHN HILL. 7 

